50-70 mph

[Matt Seabrook]

Easily calculated(estimated) by taking the top speed (112mph) and the peak power (120bhp)

P=0.5*rho*A*Cd*U^3

rho, the density of air is about 1.2kg/m^3

Cd=2/1.2kg/m^3*120bhp / (112mph)^3/1.7m^2 = 0.68

If you say so  

I bet he's great fun at parties?  

[TerryC]

Any boffins worked out the frontal area of a Westfield yet?

I have a son who would be interested for a project he's doing.

ta

[geelhoed]

I'm the hit of the party usually,  they all go home with soiled pocket protectors!

My estimate was of the frontal area was 1.7m^2

1.65m wide at the bottom, 65cm high and on top of that a rectangle of 50cm high and 1.25m  wide. Perhaps somewhat overstimated but well....

[Bob Green]

So how do you smash the Atom?

[Mitchamidilly]

My estimate was of the frontal area was 1.7m^2

Hmmm, that gives a CdA of around 12.81 using the Cateringvan Cd of 0.7. That worse than a Jeep Grand Cherokee  

I know the Westie is not aerodynamic but surely they can't be that bad?

[Darkspeed]

So how do you smash the Atom?

Let your drunk mate take it out for drive on greasy roads  

[Keith@FM]

My estimate was of the frontal area was 1.7m^2

Hmmm, that gives a CdA of around 12.81 using the Cateringvan Cd of 0.7. That worse than a Jeep Grand Cherokee  

I know the Westie is not aerodynamic but surely they can't be that bad?

Yes, they're that bad When we were doing the timed acceleration runs, the rate of acceleration dropped off pretty spectacularly above 90 mph.

0-60 in 4.7 seconds

0-90 in 10.8 seconds

0-100 in 14.8 seconds

None of this is a surprise to a Westfield owner of course, but it was dramatic to see in the numbers. We were going to redo the testing with the windscreen off to cut down the frontal area, but then the tester discovered how much fun the car was to drive sideways and proceeded to be a complete hoon. As you do.

[geelhoed]

I could tell you that the time to accelerate to a certain speed, lets say X which is a fraction of the top speed U0, is

T= [(X*U0)^2]/[2*P] * [ 1+ 2/5*X^3 + 2/8*X^6 + 2/11*X^9 + ..... ]

But you all'd be bored!

[Matt Seabrook]

Just been out in the sprint car and now have a little data. 50 to 70 managed 1.46 seconds with cold tyres spinning wheels a little when the car comes on to cam so if I got some heat into the tyres it ma be a little quicker.

[pistonbroke]

I could tell you that the time to accelerate to a certain speed, lets say X which is a fraction of the top speed U0, is

T= [(X*U0)^2]/[2*P] * [ 1+ 2/5*X^3 + 2/8*X^6 + 2/11*X^9 + ..... ]

But you all'd be bored!

Us lot bored ! how could we be  

did you factor in fact that the earth is flat for a fact  

[VX2L16V]

50-70 3.1s

*but* I haven't widebanded it... yet

bung gets chopped off exhaust tuesday & new one welded on. 'bout time too!